The 30-year-old's career has gone full circle after signing for his boyhood club this summer.
Carroll spent five years with Newcastle before joining Liverpool in 2011, and the strike insists his a different person this time around.
He told the club website: "I've got no doubt that I was daft when I was here, and no doubt that I was daft for a couple of years after as well.
"But I met my missus, and we've got four kids living at home now, we've got animals, we've got responsibilities.
"There's no more behaviour like it was, you know.
"I was stupid, I was young, and I was carried away with the lifestyle that I had.
"Now it's completely different.
"I'm actually a dad, I've grown up, and got responsibilities, so… I've got a purpose."